Zhinan Shi

Experimental research on solid circulation in a twin fluidized bed system

Abstract A twin fluidized bed solid circulation system, in which two adjacent fluidized beds exchange solids, was developed for coal gasification to produce middle heating value gas. The effects of bed material, operation velocity, and bed structure on the solid circulating rate were tested at a small-scale test facility. Experimental results showed that the solid circulation rate of the system could be adjusted by changing gas velocities of two beds and could attain 30–40 times of the fuel feed rate, which would meet the demands of heat supply to an endothermic process of a gasifier. On the basis of experiments, reasonable operation and design parameters were put forward, which can be used to as a reference for the commercial gasifier design. A mathematical model was erected to calculate the solid circulation rate of the system, and it could predict well the solid flow rate through a horizontal orifice by comparison with experimental data.

Effects of support property on the catalytic performance of CeO2-ZrO2-CrOx for 1,2-dichloroethane oxidation

Abstract HZSM-5, Al 2 O 3 , TiO 2 and SiO 2 supported CeO 2 -ZrO 2 -CrO x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane (DCE), as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N 2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), ammonia-temperature-programmed desorption (NH 3 -TPD) and hydrogen temperature-programmed reduction (H 2 -TPR). The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20%CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order: 20%CZCr/HZSM-5>CZCr>20%CZCr/TiO 2 >20%CZCr/Al 2 O 3 >20%CZCr/SiO 2 .